Low resistance interface metal for disk drive suspension component grounding

ABSTRACT

A stainless steel suspension component such as a mount plate is chemically activated by exposure to an activating solution. Gold is then spot plated onto the mount plate in the activated area using an elastomeric mask that is clamped over the mount plate. A component may then be bonded to the gold bond pads. The component may include a PZT microactuator bonded to the gold bond pads using a conductive adhesive such as silver epoxy. The gold acts as an interface metal that provides to a low resistance and environmentally robust ground path for the microactuator.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No. 12/965,661filed Dec. 10, 2010, which claims priority from U.S. Provisional PatentApplication No. 61/286,941 filed Dec. 16, 2009, which is herebyincorporated by reference as if set forth in its entirety herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of disk drive suspensions. Moreparticularly, this invention relates to the field of a low resistanceinterface metal for disk drive suspension component grounding.

2. Description of Related Art

Good electrical connections must be made between a suspension'sstainless steel (SST) body on the one hand, and other components such assuspension flexure circuit bond pads, grounding wires, flying leads, ormicroactuators such as piezoelectric (PZT) devices on the other hand.Microactuators are used to cause very fine control and movement of thesuspension's read/write head, and are often mounted directly to themount plate.

One prior art method of creating that electrical connection is by usingsilver (Ag) epoxy as an adhesive between the mount plate, which isgrounded, and the other component. However, the inherently chromium (Cr)rich passivation layer which forms on the surface of the stainless steeltends to create a high resistance barrier on that surface. Some of thesilver epoxies that have been used in the past as conductive adhesivessuffer the drawback of having a resistance that increases in response totemperature, humidity, and/or time. One of the silver epoxies whoseresistance increases the least over temperature, humidity, and time,suffers the additional disadvantage of containing mercury which must behandled as a hazardous material.

Designing a low resistance interconnect from the PZT to the mount plateis further complicated by the inherent mechanical strain induced by the20 nm/V displacement of the PZT when driven up to 20 volts at anoperational frequency of 1-30 KHz, which renders connections which relyon soft materials such as solder inadequate for the demanding cyclicloads experienced at the PZT/mount plate interface.

SUMMARY OF THE INVENTION

In the discussion that follows, the term “mount plate” shall be used forsimplicity of discussion, it being understood that the term appliesequally to a base or load beam portion of a suspension in a suspensiondesign that does not use a traditional mount plate per se. Thus, theterm “mount plate” as used in the disclosure herein and encompasses botha traditional mount plate as well as equivalent base portions inalternative suspension designs. Furthermore, some DSA suspension designsplace the PZT entirely on the stainless steel load beam. The presentinvention is equally applicable to improving the connection between thePZT and the load beam in such designs.

According to the invention, a mount plate is chemically activated in adesired area and then spot plated with gold (Au) to form gold bond padson the mount plate only in the area(s) where an electrical connectionwill be required. The mount plate can be a mount plate that has beenpreviously stamped (formed). In an alternative embodiment that iscurrently believed to be less favored, the gold may be spot plated ontoa mount plate that is thereafter stamped. In still a further embodiment,the mount plate is plated with gold, and the gold is thereafter strippedto leave only a gold bond pad in the particular area desired. In yetanother embodiment this low resistance interfacial metal may be appliedby laser brazing to either the raw stainless steel sheet stock beforethe mount plate or other components are formed into the sheet stock, orto an intermediate component.

The gold bond pads can then be used to bond the mount plate bond pads toany of flexure bond pads, gold plated flying leads, metalized surfacesof PZT microactuators, or other components. The gold plated bond padscan also be used for thermosonic welding of copper wires or othermaterials and structures to the gold bond pads, although gold-to-gold isgenerally preferred for thermosonic bonding. It is believed that thegold bond pads would also provide a viable solder interface to thestainless steel mount plate. The gold bond pads on the stainless steelmount plate have been experimentally determined to have much lowersurface resistance than the silver epoxy bonds of the prior art,especially after prolonged exposure to humid environments.

In one aspect, the invention is of a disk drive suspension, thesuspension having at least a portion thereof such as a mount platecomprising stainless steel, a portion of the stainless steel beingchemically activated and then selectively plated with gold using anelastomeric plating mask, and an electrical component such as a PZTmicroactuator bonded to the gold bond pad such as by silver epoxy, thegold bond pad and the stainless steel mount plate providing a groundpath for the microactuator, the gold bond pad providing an interfacemetal between the piezoelectric and the stainless steel that makes for alow resistance path to ground that is highly resistant to environmentaldegradation compared prior art techniques for bonding a microactuator tothe stainless steel mount plate.

In another aspect, the invention is of a method of forming a groundconnection to a stainless steel suspension component, the methodcomprising: chemically activating a stainless steel surface of thesuspension component to produce a chemically activated surface thereofsuspension component; pressing a resilient plating mask against thesuspension component, the resilient plating mask having an aperturetherein that extends to the chemically activated surface of thesuspension component, the portion of the suspension within the aperturedefining a plating surface; causing a gold electroplating electrolyte toflow into the aperture of the resilient plating mask and thereby contactthe plating surface; electroplating gold onto the plating surfaceexposed within the aperture of the pliable plating mask to create a spotgold plated portion of the suspension component; and bonding anelectrical component to the spot gold plated portion, the gold providinga high quality ground connection to the stainless steel component.

Exemplary embodiments of the invention will be further described belowwith reference to the drawings, in which like numbers refer to likeparts. The drawing figures might not be to scale, and certain componentsmay be shown in generalized or schematic form and identified bycommercial designations in the interest of clarity and conciseness.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a prior art dual stage actuated suspension,to which the present invention may be applied;

FIG. 2 is a graphical representation of a spot plating apparatus adaptedfor selectively metalizing a disk drive suspension according to oneaspect of the invention;

FIG. 3 is a simplified side cutaway view of the area around spot platingelastomeric plating mask 36 and the plating target in FIG. 2;

FIG. 4 is a flow chart of a process for selectively creating a lowresistance metal interface on a suspension component according to thepresent invention;

FIG. 5 is a side cutaway view of a microactuator mounted to thesuspension component according to the invention;

FIG. 6 is a graph of surface resistance of a suspension component havinga low resistance interface metal bond pad according to the presentinvention, versus the surface resistance of a prior art electricalconnection;

FIG. 7 is a box plot of post-HAST resistance at the suspension level oftwo improved contacts according to the present invention and a prior artcontact, measured at electrical test conditions of 0.1 V and 100 KHz;

FIG. 8 is a box plot of post-HAST resistance at the suspension level oftwo improved contacts according to the present invention and a prior artcontact, measured at electrical test conditions of 0.1 V and 1 KHz;

FIG. 9 is a box plot of post-HAST resistance at the mount plate level oftwo improved contacts according to the present invention and a prior artcontact, measured at electrical test conditions of 0.1 V and 100 KHz;and

FIG. 10 is a side cutaway view of a wire bonded to a stainless steelsuspension component according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the invention, a mount plate or its equivalent in asuspension for a disk drive such as a magnetic hard disk drive is spotplated with gold to create gold bonding pads on the mount plate. Theresult is that various components can be electrically bonded to thestainless steel mount plate via the low resistance, high bond qualitymetal interface.

Gold spot plating is, by itself, previously practiced in other contexts.Typical gold spot plating involves clamping a plating mask made of anelastomeric material such as precision molded silicone rubber that isopened and closed using a clamshell-type mechanism over the part. Thesilicone rubber creates a watertight seal preventing the coveredportions of the part from being plated.

U.S. Pat. No. 7,148,085 issued to Abbott et al. discloses an integratedcircuit leadframe that is gold spot plated by first covering theleadfame with a noble metal, preferably palladium, and then plating withgold only in the selected areas using a rubber mask that is clamped ontothe lead frame, and a plating solution that is jetted at the exposedportion of the leadframe that is to be plated. The gold plated portionof the leadframe is then soldered using a tin/lead, tin/indium,tin/silver, tin/bismuth solder, or is attached using a conductiveadhesive. U.S. Pat. No. 6,656,275 issued to Iwamoto discloses a portiongold plating system that plates gold only on the inner leads of a tapeautomated bonding (TAB) tape, by pressing a mask onto the tape andspraying a plating solution onto the tape through a hole. U.S. Pat. No.5,305,043 issued to Johnson and U.S. Pat. No. 5,045,167 issued to Palnikalso disclose spot plating using plating masks. These techniques, whichdo not involve gold being plated onto stainless steel, may be adaptedand modified for use in the present invention.

FIG. 1 is a top plan view of a prior art dual stage actuated (DSA)suspension, to which the present invention may be applied. Suspension 10includes a base plate 12, a load beam 16, a spring region 14 thatdefines a flexible hinge, and two piezoelectric (PZT) microactuators 18disposed somewhere between mount plate 12 and load beam 16. Mount plate12 is typically stainless steel. Typically, PZTs 18 are adhered to mountplate 12 via conductive silver epoxy, the epoxy contacting metallizedsurfaces of the PZT on one side and the surface of the stainless steelmount plate 12 on the other side.

It can be difficult to plate other metals directly onto stainless steel.In order to do so, the stainless steel must be specially prepared oractivated. U.S. Pat. No. 4,422,906 issued to Kobayashi discloses amethod for directly plating gold onto stainless steel, includingactivating the stainless steel surface prior to the plating operation.Kobayashi is hereby incorporated by reference for its teachings ofpreparing a stainless steel surface for gold plating, and for platinggold onto the stainless steel, as if fully set forth herein.Specifically, gold may be plated directly onto stainless steel using amethod which comprises the steps of:

dipping or otherwise exposing stainless steel in an activating solution;

subjecting the activated stainless steel to cathode electrolyticactivation; and then,

electroplating the cathodically electrolyzed stainless steel with gold.

The activating solution used in the first step is preferably an aqueousmixed acid solution containing, based on the weight of the solution:

(i) 3 to 20% by weight of hydrochloric acid;

(ii) 2 to 30% by weight of sulfuric acid;

(iii) 0.1 to 5% by weight of a nonionic or cationic surface activeagent; and

(iv) 0.1 to 20% by weight of 2-pyrrolidone or its N-alkyl derivative.

More preferably, the activating solution used in the first step is anaqueous mixed acid solution containing, based on the weight of thesolution:

(i) 3 to 10% by weight of hydrochloric acid;

(ii) 0.5 to 4% by weight of nitric acid;

(iii) 2 to 15% by weight of sulfuric acid;

(iv) 1 to 5% by weight of acetic acid;

(v) 3 to 10% by weight of citric acid;

(vi) 0.1 to 3% by weight of a nonionic or cationic surface active agent;

(vii) 0.1 to 10% by weight of 2-pyrrolidone or its N-alkyl derivative;and

(viii) 1 to 5% by weight of an acetylenic glycol.

In the present embodiment the gold layer is deposited onto the stainlesssteel mount plate using any suitable method, including withoutlimitation the methods taught by Kobayashi. Once the stainless steel hasbeen activated by exposure to the chemical activating solution, it canthen be selectively gold plated.

FIG. 2 is a graphical representation of a spot plating apparatus adaptedfor selectively metalizing disk drive suspension mount plates or othersuspension component according to one aspect of the invention. Spotplating apparatus 20 includes a spot plating cell 22, a stirrer 24 orother means to create turbulent flow for good mixing of the solution, ananode cell 30 having a plating anode 42, electrolytic gold platingsolution 32, a pump 34, a controlled voltage source or controlledcurrent source 40, a support tray 50 which may be raised and lowered, anelectrical connection 44 from current source 40 through which theplating current will flow to the mount plate 12 or other suspensioncomponent (shown in FIG. 3), and resilient plating mask 36. Resilientmask 36 would typically, although not necessarily, take the form of aclamshell like device having two halves that are clamped together overthe activated stainless steel suspension component. When the clamshellis opened, plating solution can be allowed to spill out and be collectedby spill collection tube 38. Alternatively, plating mask 36 could belocated above spot cell 22 so that electrolyte 32 runs out under forceof gravity before plating mask 36 is opened, and/or pneumatic tubescould be used to clear the electrolyte from plating mask 36 before it isopened, in order to reduce or eliminate electrolyte spill.

FIG. 3 is a simplified side cutaway view of the area around spot platingresilient plating mask 36 and the plating target in FIG. 2. The platingtarget 15 could be only mount plate 14 before it is welded to springhinge 14 and load beam 16, or it could be a stock sheet of stainlesssteel material before that stock material is formed by patterning,etching, and working by stamping and/or bending, to form base plate 14,either separately from spring 14 and load beam 16 or integrally with it.Plating target 15 could also be a load beam or other component to whichPZT 18, or other electrical component such as a flexible circuit lead,will be electrically connected. More generally, plating target 15 couldbe any stainless steel part.

In an illustrative embodiment, elastomeric plating mask 36 includes twohalves that are clamped against opposite sides of plating target 15. Onehalf includes a chamber 37 into which the electrolyte flows, and anaperture 39 that allows the electrolyte to reach the surface 13 whichdefines the area of plating target 15 to be gold plated. One theelastomeric plating mask 36 is clamped firmly in place, electrolyte ispumped into the chamber, voltage or current source 40 is turned on, andarea 13 is plated to the desired plating depth. The plating processpreferably plates area 13 on target 15 with at least 95% purity gold.This differs from gold plating techniques that have previously been usedto plate gold onto stainless steel objects such as jewelry, in whichtypically a thin layer of copper is flash plated onto the stainlesssteel for wetting purposes, followed by a thin layer of nickelelectrodeposited on the copper, and finally followed by anelectrodeposited gold layer having a significant percentage of nickeland/or rhodium such that the electrodeposited gold layer is less than95% gold, with the nickel layer acting to prevent migration of copperinto the gold layer. Plating target 15 is held firmly by a mechanismsuch as clamp 52. The plating current flows through electricalconnection 44, through support tray 50 which can be raised and lowered,and to plating target 15.

FIG. 4 is a chart of a process for selectively creating a low resistancemetal interface on a suspension component according to the presentinvention. The process includes the steps of: chemically activating astainless steel surface using a chemical activation bath; pressing anelastomeric mask to mask off areas of the stainless steel other than thearea(s) to be plated; electroplating high purity gold onto the exposedareas; and heat treating the component.

FIG. 5 is a side cutaway view of a microactuator mounted to aselectively gold plated base plate according to the invention. Baseplate 12 (or other portion of the suspension to which PZT 18 will bebonded) has activated area 60 which was activated by the activatingsolution, and gold layer 62 defining a gold bond pad that waselectrodeposited in the plating apparatus 20 of FIG. 2 or other suitableapparatus. Silver epoxy 64 bonds the lower surface of PZT 18, whichpreferably has been metalized in order to conduct the actuation voltageover the entire surface of the PZT which defines the negative electrodeof the PZT, to base plate 12. A microactuator driving voltage, shownbeing applied in generalized form as driving voltage lead wire 80, iselectrically connected to 1^(st) metallized surface 17 of PZT 18. PZT 18is grounded through its second metallized surface 19 to base plate 12through gold bond pad 62. Also shown are intermediate metal layers 70,71, such as copper and nickel, respectively, as will be discussedfurther below.

Preferably, after plating the stainless steel part is then heat treated.Heat treating produces a gold/SST alloy at the interface between the twometals. Gold layer 62 is preferably greater than 0.1 μm thick in orderto maintain sufficient purity of the gold at the surface, even aftertaking into account some diffusion of gold into the stainless steelduring subsequent heat treating. Also, gold layer 62 should be at least0.1 μm thick to prevent too much of the gold from being removed by thechemical duburring process which is typically applied to suspensionsprior to final assembly in order to minimize the shed of contaminatingmetal particles which could damage the hard disk surface.

FIG. 6 is a boxplot of surface resistance of a gold bonding pad on amount plate produced according to the present invention producing goldlayers of 0.25 μm and 0.40 μm thick, versus the surface resistance ofprior art electrical connection according to the prior art. The graphshows significantly reduced electrical resistance for electricalcontacts to stainless steel according to the invention, than for theprior art connection of silver epoxy directly onto stainless steel.Specifically, resistance for contacts of the present invention utilizinggold layers of 0.40 μm and 0.25 μm thick, were both less than 1.0Ω, ascompared to 9-18Ω for the conventional contact of silver epoxy directlyonto stainless steel. The test data therefore shows a dramaticimprovement in the electrical contact from the PZT to the stainlesssteel using the invention. The test was conducted using a PZT driven at1000 Hz, and measured per ASTM-8116 which specifies a 4-pin surfaceresistance measurement.

Additionally, HAST testing was performed on the connection of theinvention, and the connection showed no visible corrosion. “HAST” standsfor Highly Accelerated Stress Test, and involves passing an electricalcurrent through a contact at elevated temperatures and humidity. Thepurpose is to approximate the effects of long term operational exposureunder normal environmental (temperature and humidity) conditions.

HAST testing was performed at 130° C. and 100% relative humidity (RH)for 120 hours, for embodiments of the invention utilizing gold layers of0.40 μm and 0.25 μm thick, and for contacts of the prior art, i.e.,without gold plating. Post-HAST resistance was measured using an LCRmeter. The results are presented in the graphs of FIGS. 7-9.

FIG. 7 is a box plot of post-HAST resistance at the suspension level oftwo improved contacts according to the present invention utilizing goldlayers of 0.40 μm and 0.25 μm thick, and a prior art contact, measuredat electrical test conditions of 0.1 V and 100 KHz.

FIG. 8 is a box plot of post-HAST resistance at the suspension level oftwo improved contacts according to the present invention utilizing goldlayers of 0.40 μm and 0.25 μm thick, and a prior art contact, measuredat electrical test conditions of 0.1 V and 1 KHz.

FIG. 9 is a box plot of post-HAST resistance at the mount plate level oftwo improved contacts according to the present invention utilizing goldlayers of 0.40 μm and 0.25 μm thick, and a prior art contact, measuredat electrical test conditions of 0.1 V and 100 KHz.

As can be seen in the graphs, after HAST exposure the resistance of thecontacts of the present invention were generally 1 to 2 orders ofmagnitude less than that of the contacts of the prior art. Nosignificant increase in post-HAST resistance was found for the goldplated contacts. Additionally, no corrosion of any gold-plated contactswas found post-HAST, and no peeling or flaking of gold post-HAST wasobserved. These test results show the significant improvements obtainedaccording to the present invention, both initially and especially afterenvironmental testing.

As an alternative to plating gold directly on the stainless steel, anintermediate layer of copper and/or nickel may be strike plated upon thestainless steel lead in order to enhance the wetability of the stainlesssteel. The nickel may be plated using a Woods Strike bath which byitself is known, being described in U.S. Pat. No. 3,645,861 issued toGarvey, which is fully incorporated by reference as if set forth herein.Furthermore, the nickel may be plated using a variation on the standardWoods Strike taught by Garvey, in which the nickel chloride andhydrochloric acid are replaced with nickel bromide and hydrobromic acid,which Garvey discloses as producing better adhesion of the nickel to thestainless steel than the standard Woods Strike bath. According toGarvey, the preferred plating bath comprises:

100-800 g/l, and preferably about 500 g/l, of nickel bromide, and

0.2-20% by weight, and preferably about 0.4% by weight, hydrobromic acidwith the plating taking place at a current density of 5-200 amp persquare foot. The resulting metallization could therefore be: stainlesssteel (SST)/Au; SST/Ni/Au; SST/Cu/Au; SST/Cu/Ni/Au; SST/Ni/Cu/Ni/Au; orother variations that will be obvious to one skilled on the art afterreceiving the teachings of the present invention. The copper and/oradditional nickel layers, when present, would constitute an intermediatemetallic layer(s) between the stainless steel and the goldbond-receptive layer. FIG. 5 shows an example of such intermediatemetallic layers. More specifically, the figure shows an intermediatemetallic layer 70 of copper, and an intermediate metallic layer 71 ofnickel thereon, before gold 62 is electroplated over nickel layer 71.

Although it is known to plate decorative SST and jewelry SST with gold,the requirements for plating a suspension SST mount plate aresignificantly different from plating decorative SST or jewelry SST atleast for the reasons that decorative or ornate objects are not usuallyoverplated with a high purity gold. Instead, such objects are typicallyoverplated with gold alloys that contains nickel or rhodium. Thealloying metals harden the gold for durability, render the gold platingmore radiant, and lower the cost as compared to pure gold. Such objectsalso typically contain a Ni layer beneath the Au to stop migration ofthe typical Cu layer under the Ni into the Au. Such ornate objects maybe of alloys. Often a thin, homogenous Cu flash deposited layerfacilitates uniform wetting. These ornamental objects may have coresthat are organics or plastic and which were made conductive by coatingthe plastic or other material with a carbon rich lacquer or a vacuumseeding process prior to electrodepositing the Cu/Ni/Au layers.Additionally, typically, a Wood's Ni Strike underlayer is applied todecorative SST and jewelry SST before the gold plating layer. Such aWoods Ni Strike underlayer prior to gold plating would preferably not beused on SST mount plates because Woods Ni can be high in chlorine, ahighly reactive trace element that is generally unacceptable to the harddisk drive industry. Furthermore, the added layers and processing stepsthat are typically used to gold plate ornamental objects add cost to thefinal product. Such added cost may be acceptable for ornamental objects,whereas in contrast the hard disk drive suspension market is fiercelycompetitive.

Although the invention could theoretically be used to bond PZT'sdirectly to a mount plate using thermosonic bonding, it is believed thatthe thermosonic bonding process may degrade the D31 (stroke length) ofthe PZT, or crack the ceramic PZT material.

Although the invention is believed to be particularly useful forimproving the quality of electrical bonds from microactuators such asPZTs to stainless steel suspension components, the invention could beadvantageously used in other types of bonds as well. For example, asshown in FIG. 10 the gold plated stainless steel suspension component112 could be bonded to gold or copper wires 180 by thermosonic bonding,or such wires 180 could be soldered to the gold contact pad 162electroplated at chemically activated area 160. Still further, acomponent could be bonded to the gold contact pad via brazing, andparticularly laser brazing. Alternatively, wire 180 could represent asuspension flexure circuit bond pad bonded to the component 112.

It will be appreciated that the term “present invention” as used hereinshould not be construed to mean that only a single invention having asingle essential element or group of elements is presented. Similarly,it will also be appreciated that the term “present invention”encompasses a number of separate innovations which can each beconsidered separate inventions. Although the present invention has thusbeen described in detail with regard to the preferred embodiments anddrawings thereof, it should be apparent to those skilled in the art thatvarious adaptations and modifications of the present invention may beaccomplished without departing from the spirit and the scope of theinvention. Accordingly, it is to be understood that the detaileddescription and the accompanying drawings as set forth hereinabove arenot intended to limit the breadth of the present invention, which shouldbe inferred only from the following claims and their appropriatelyconstrued legal equivalents.

We claim:
 1. A method of forming a ground connection from a stainlesssteel disk drive suspension body to a microactuator, the methodcomprising: chemically activating a surface of the stainless steel diskdrive suspension body; using a mask to isolate a portion of thestainless steel disk drive suspension body thereby defining an isolatedportion of the stainless steel disk drive suspension body; causing aplating solution to contact the isolated portion; plating a corrosionresistant metal onto the isolated portion of the stainless steel diskdrive suspension body, thereby forming a corrosion resistant plated areaon the disk drive suspension body, the corrosion resistant metal beingin direct electrical communication with the stainless steel disk drivesuspension body without any electrical insulator therebetween; applyinga conductive adhesive to mechanically and electrically bond an electrodeof the microactuator to the corrosion resistant plated area; andgrounding the suspension body; whereby a ground path is provided fromthe microactuator, through the conductive adhesive, through the platedcorrosion resistant metal, and through the stainless steel disk drivesuspension body.
 2. The method of claim 1 wherein the disk drivesuspension body is selected from the group consisting of a base plateand a load beam.
 3. The method of claim 1 wherein the corrosionresistant metal comprises gold, and the corrosion resistant metal platedarea defines a gold plated area.
 4. The method of claim 3 furthercomprising plating an intermediate metal layer comprising at least oneof copper and nickel onto the chemically activated surface of thestainless steel suspension body prior to plating the corrosion resistantmetal, the corrosion resistant metal being plated over the intermediatemetal layer.
 5. The method of claim 3 wherein the conductive adhesive issandwiched between the microactuator and the gold plated area.
 6. Themethod of claim 3 wherein the disk drive suspension body is a disk drivesuspension base plate, and the conductive adhesive is sandwiched betweenthe microactuator and the gold plated area of the disk drive suspensionbase plate.
 7. A method of forming a ground connection from a stainlesssteel disk drive suspension body component to a piezoelectric actuator,the method comprising: chemically activating areas of a sheet ofstainless steel material thereby defining a plurality of chemicallyactivated areas; isolating portions of the stainless steel sheetmaterial, the isolated portions respectively including at least parts ofthe chemically activated areas; locally spot plating gold onto theisolated portions, the spot plating producing locally gold plated flatsurfaces, the gold being in direct electrical communication with thestainless steel sheet without any insulating layer therebetween; forminga plurality of separate disk drive suspension body components from thestainless steel sheet, said plurality of disk drive suspension bodycomponents including at least a first stainless steel suspension bodycomponent and a second stainless steel disk drive suspension bodycomponent, each of the first and second disk drive suspension bodycomponents including respective ones of the locally gold plated flatsurfaces; and sandwiching conductive adhesive between the locally goldplated flat surface of the first disk drive suspension body componentand a ground electrode of the piezoelectric actuator therebyestablishing a ground path from the ground electrode of thepiezoelectric actuator through the sandwiched conductive adhesive,through the locally gold plated flat surface, and to stainless steeldisk drive suspension body component.
 8. The method of claim 7 whereinthe disk drive suspension body component is selected from the groupconsisting of a base plate and a load beam.
 9. The method of claim 7further comprising plating an intermediate metal layer comprising atleast one of copper and nickel onto the stainless steel disk drivesuspension body component prior to plating the gold, the gold beingplated over the intermediate metal layer.
 10. The method of claim 7further comprising: after the locally spot plating, heat treating thestainless steel sheet.
 11. The method of claim 7 wherein: the isolatingstep comprises pressing a resilient plating mask against the stainlesssteel, the resilient plating mask having an aperture therein thatextends to the chemically activated area, an area within the aperturedefining a plating surface; and the step of locally spot plating goldcomprises: causing a gold containing electrolyte to flow into theaperture of the resilient plating mask and thereby contact the platingsurface; and electroplating gold onto the plating surface exposed withinthe aperture of the resilient plating mask to create a spot gold platedarea.
 12. The method of claim 7 wherein the chemical activation isperformed using a chemical activating solution comprising: (i) 3 to 20%by weight of hydrochloric acid; (ii) 2 to 30% by weight of sulfuricacid; (iii) 0.1 to 5% by weight of a nonionic or cationic surface activeagent; and (iv) 0.1 to 20% by weight of 2-pyrrolidone or its N-alkylderivative.
 13. A method of forming a ground connection from a stainlesssteel disk drive suspension body to a microactuator, the methodcomprising: chemically activating a surface of stainless steel byapplying an acid solution thereto; plating an intermediate metal layeronto the stainless steel surface, the intermediate metal layercomprising at least one of nickel and copper; plating gold onto theintermediate metal layer such that the gold and the intermediate layerare in direct electrical communication with the stainless steel surfacewithout any electrical insulator between the gold and the stainlesssteel surface, the plated gold defining a gold plated surface; formingthe stainless steel into a disk drive suspension body component, thestainless steel disk drive suspension body component being selected fromthe group consisting of a base plate and a load beam; and disposingconductive adhesive between a ground electrode of the microactuator andthe gold plated surface to mechanically bond the microactuator to thesuspension body component and to electrically ground the microactuatorthereto; whereby a ground path is provided from the microactuator'sground electrode through the conductive adhesive, through the goldplated surface, and to the stainless steel of the suspension body. 14.The method of claim 13 wherein the step of forming the stainless steelinto a disk drive suspension body is performed after the gold plating.15. The method of claim 13 wherein the step of forming the stainlesssteel into a disk drive suspension body is performed before the goldplating.
 16. The method of claim 13 further comprising: after the goldplating step, heat treating the stainless steel including the goldplated surface thereon.